Preparation of dithiolium compounds



United States Patent Ofi Patented June 1, 1965 3,1?i6395 PREPARATIGN F DETHIOLIUM COMPGUNDS Erwin Klingsherg, Mountainside, N.J., assignor to American Cymanrid Company, Stamford, Conn, a corporation of Maine No Drawing. Filed Aug. 2, 1963, Ser. No. 299,473 4 Claims. (Cl. Mil-294.8)

wherein each of the R and R groups is hydrogen, lower alkyl, phenyl, naphthyl, thienyl, furfuryl, pyridyl or phenyl lower alkyl. When R and/or R is a cyclic substituent, it may contain up to three halo (e.g., chloro and bromo), nitro, lower alkyl, lower alkoxy, di-lowc-r alkylarnino, lower alkanoyl, lower aikanoyloxy, sulfo or carboxy substituents.

The ditbioliurn salts of Formula I are prepared by treating a trithione (i.e., a l,2dithiole-3-thione) with an organic peracid to effect oxidation of the nucleus, thereby forming a dithiolium cation according to the following equation:

wherein R and R are defined as above. This reaction, in general, involves treating the trithione with the peracid at a temperature below 40 C., preferably below room temperature, in a solvent inert to the peracid, such as acetone or methylethylketone, and separating the resulting bisulfate salt. This water-soluble salt may be converted to other salts by addition of bromide, iodide, thiocyanate, lluoborate, picrate or perchlorate anions, or the like.

Tri'hitones which may be used in the preparation of the corresponding dithiolium compounds of this invention include such trithiones as fi-ethylor -methyl-l,2-dithiole-3 -thione, 4,5-diamethyl-1,2-dithiole-3-thione, 4-butyl-5-rnethyl-l ,2-dithiole-3-thione, 4-phenyl-5-methyl-1,2-dithiole-3 thi one, 4-(p-nitrophenyl)-1,2-dithiole-3-thione, 4-methyl-l ,2-dithiole-3 -thione, 4-ethyl-1,2-dithiole-3-thione,

S-(Z-furfnryl) -l, 2-dithiole-3-thione, 4-phenyl-1,2-dithiole-3 -thione,

4-p-tolyl-l ,2-dithiole-3-thione, 4-p-t-butylphenyl-l ,2-dithiole-3-thione, 5-phenyl-1,2-dithiole-3-thione,

S-a-na hthyl-I ,2-dithiole-3-thione, S-(p-dirnethylarninophenyl -1 ,2-dithiole-3 -thione, 5 (p-chlorophenyl)-1,Z-dithiole-S-thione,

5 (p-anisyl) -l ,Z-dithiole-B-thione,

5-p-tolyl-l ,2-dithiole-3 -thione,

5- (o-anlsyl) -l,2-dithiole-3-thione,

5-( Z-thienyl l ,2-dithiole-3-thione,

5-( 3 ,4-dirnethoxyphenyl +1 2-dithiole-3-thione, 5-(S-methyl-Z-methoxyphenyl) -1,2-dithiole-.3-thione,

Lrnethyl-Sphenyll ,Z-dithiole-B thione, 4-rnethyl-5- (p-anisyl) -l ,2-dithiole-3 -thione, 4-rnethyl-S (2,4-xylyl)-1,2-dithiole-3-thione, 4-rnethyl-5-( 3,4-dimethoxyphenyl -l ,(Z-dithiole-B-thione 4,5-diphenyll ,2-dithiole-3-thione, 4 (i3 'sulfophenyl trithione, 4-( 3 '-propionyl phenyl) 4- (il-phenylpropyl )trithionc, 4- {p acetoxyphenyl trithione, 4-( 3-s-ul-fophenyl) trithione, 4( 3-propiony-lphenyl)trithione, 5-(2-pyridy1)trithione, 4-( 3 -methyl p yri dyl) trithione, 4-e thyl -5 4' p yridyl trithione, 4-butyl-5(4-pyridyl)trithione and the like.

Compounds of Formula I are readily converted to new cationic dyestuffs by condensation with a tertiary aromatic amine having a free para position: The dithioliurn salts react at the 3- (or 5-) position when this position is free. These dyestuffs color acrylic fibers intense shades when applied by customary methods. The condensation reaction proceeds readily in an inert solvent such as an alcohol (e.g., ethanol) at temperatures above 60 C. up to reflux. Yields are often improved by the use of a mild oxidizing agent such as potassium persulfate. The product may be isolated by conventional methods and purified by recrystallization. if the dye still contains a free 5-pcsition, repetition of the condensation reaction with a second molecule of tertiary amine gives dyes containing two tertiary amino groups.

The following examples, in which parts are by weight (unless otherwise specified) and degrees are in centigrade, are presented to illustrate the present invention further.

Example 1 A solution of 6 parts of 4-phenyl-1,2-dithiole-3-thione in parts by volume of acetone is chilled and stirred while 16 parts of 40% peracetic acid is slowly added. After the reaction is complete, the yellow product is filtered, washed and crystallized from alcohol.

Example 2 bright orange iodide. Picric acid gives the bright yellow picrate.

Example 3 (EH26 (SE93 I HSOF s-s A solution of 2 parts of 4-neopentyl-l,2-dithiole-3- thione in 50 parts by volume of acetone is treated with 6 parts of 40% peracetic acid dissolved in 10 parts by "a a volume of acetone. After completion of the reaction, the crystalline produce is obtained by filtration.

Example 4 a Q SS This product is obtained by the procedure of Example 3, starting with 4-'nethyl-1,2-dithiole-3-thione.

Example 5 This product is obtained by the procedure of Example 2, starting with 5-p-anisyl-l,2-dithiole-3-thione.

Example 6 l im H504 This product is obtained by the procedure of Example 2, starting with 5-(2-thienyl)-1,2-dithiole-3-thione.

Example7 7 GE N at m HSOF To a solution of 2.5 parts of 5-(p-dimethyl-aminophenyl)-1,2-dithiole-3-thione in 800 parts by volume of acetone is gradually added a solution of 5.0 parts by volume of 40% peracetic acid in ,50 parts by volume of acetone. The red-violet product is purified by crystallization from acetic acid.

Example 8 m1- s--s L- Fifty parts by volume of diethyl fumarate and parts of sulfur are boiled together for two hours. The reaction product is fractionated to yield S-carbethoxy-1,2-dithioletrate extracted three times with fifty parts of the ether each time. The ether extracts are combined, dried and evaporated. Crystallization of the solid from hexane yields S-carbethoxy-l,2-dithiole-3-thione as a purplish solid melting at about 6566 C.

One part of the S-carbethoxy-l,2-dithiole-3-thione is saponified by dissolving in a solution of five parts of sodium sulfide nonahydrate in 200 parts of water. The solution is allowed to stand at room temperature until saponification is complete. then crystallization of the reaction product from benzenehexane yields the compound 5-carboxy-1,2-dithiole-3- thione as a purple-brown crystalline solid melting at about 136139 C. (with dec.).

To 4.6 parts of S-carboxy-l,2-dithiole-3-thione dissolved in 125 parts of acetone are added, gradually at C., 15 parts of peracetic acid. The product, dithiolium hydrogen sulfate, is precipitated as the iodide by treat- 7 ment with hydriodic acid. The iodide crystallizes from propanol as orange needles melting at 179-18l C. (with dec.).

Example 9 This product is prepared by the procedure of Example 1 starting Wth an equivalent amount of 5-(1-naphthyl)- 1,2-dithiole-3-tl1ione, in place of the dithiolethione used therein.

Example 10 C10 HS 0 4 m 1, starting With'an equivalent amount of S-(p-chloro This product is prepared by the procedure of Example phenyl)-l,2-dithiole 3-thione, in place of the dithiolethione Acidification with HCl and used therein.

Example 11 This product is obtained by the procedure of Example 2, starting with an equivalent amount of 5-(furfuryl)-l,2- dithiole-3-thione in place of the dithiolethione used therein.

Example 12 This product is obtained by the procedure of Example 2, starting with an equivalent amount of 5-(4-pyridyl)-l,2- dithiole-3-thione in placed the dithiolethione used therein.

Example 13 This product is obtained by the procedure o'r' Example 2, starting with an equivalent amount of 5-benzyl-1,2- dithiole-3-thione in place of the dithiolethione used there- 1n.

Example 14" HSOF I ss This product is prepared by the procedure of Example 1, starting With an equivalent amount of S-(p-acetoxypheny1)-1,2-dithiole-3-thione in place of the dithiolethione used therein.

Example 16 This product is prepared by the procedure of Example 1, starting with an equivalent amount of S-(p-acetylphenyl)-1,2-dithile-3-thione in place of the dithiolethione used therein.

Example 17 This product is prepared by the procedure of Example 1, starting with an equivalent amount of S-(p-carboxyphenyl)-1,2-dithiole-3-thione in place of the dithiolethione used therein.

Example 18 This product is prepared by the procedure of Example 1, substituting an equivalent amount of perbenzoic acid for the peracetic acid used therein.

Example 19 6 Q H804 ss This product is prepared by the procedure of Example 1, substituting an equivalent amount of perphthalic acid for the peracetic acid used therein.

I claim: 1. A process of preparing the compound of the formula:

Rl' HS 04- wherein R and R are individually selected from the group consisting of lower alkyl, phenyl, naphthyl, hydrogen, thienyl, furfuryl, pyridyl and phenyl lower alkyl, said R and R groups, when cyclic, bearing up to three substituents selected from the group consisting of halo, nitro, lower alkyl, lower alkoxy, di-lower alkylamino, lower alkanoyl, lower alkanoyloxy, sulfo and carboxy, which comprises reacting a compound of the formula:

References Cited by the Examiner Walter et al.: Annalen der Chernie, vol. 649 (1961), pp. 88 and 89.

IRVKNG MARCUS, Primary Examiner.

NICHOLAS RIZZO, Examiner, 

1. A PROCESS OF PREPARING THE COMPOUND OF THE FORMULA: 